Wrench



R. LEHNHOFF.

WRENCH.

APPLICATION FILED PM! 23, 1919.

Patented Aug 3, 1920.

RUDOLPH LE NH FF, or. BURNHAM, ILLInoIs. L

. f wnmacn.

To all ivhom it may concern Be it known that I, RUDOLPH Lnrnfnorr, acitizen of the United States, residin of Illinois, have inventedacertain new and useful Improvement in Wrenches, of which the followingis a full, clear, concise, and exact description, reference being had tothe accompanying drawings, forming a part of this specification. 7

My invention relates to improvements in wrenchesand has specialreference to an improved monkey wrench.

The object of my invention is to provide a wrench of the character knownas monkey wrench which can bereadily manipulated to permit the movablejaw to be drawn out a back 11 and open at its-front.

freely, in which the said jaw shall be automatically withdrawn, andwhich shall be so constructed that the automatic retractionof the jawcan be readily controlled to permit it to be retracted substantiallyinstantaneously or to be retracted slowly.

A further object of m invention is to provide a wrench of the c aracteroutlined,

in which the cooperating screw and worm for relative movement of the twojaws of the wrench shall be normally locked in engaging relation andshall have a simple trigger release.

My invention consists in a wrench having two relatively movable jaws,screw means for adjusting said jaws, trigger means for releasing thescrew means for permitting the free relative movment of thejaws,-;spring means for closing the jaws and means" for controlling theaction of the spring in closing the jaws.

My invention also consists in the several features of construction andin the combinations and relations of parts whereby I am enabled toattain the above-mentioned and other objects and L all as hereinafterdescribed, and particularly pointed out in the appended claims; 1

For a clear understanding of my invention, attention isdirected to saiddrawings, in which: i

Figure 1 is a longitudinal sectional view substantially on the line 1-1of Fig. 3 and showing the two jaw members on the wrench in closedrelation and side elevation;

at i. Bnrnham, in the county of Cookand tate I Application filed May 23,1919. Serial No. 299,1 94.

Fig.2 is a view similar to 1 but showingvthe jaws of the wrenchseparated; and

igs. 3 and 1 are detailed cross-sectional views taken substantially onthe lines.33 and 4-4 of Fig. 1.

The wrench comprises the two main members 5 and 6, the member 5 beingprovided with a jaw 7 and the member 6 with a 00- operating jaw 8. Thesemembers are arranged parallel with each other and the member 5 withitsjaw 7 can be moved lon- .Speciflcat1on of Letters Patent. v PatentedAug, 3,1920. 1

gitudinally relatively to the member 6 to vopen the wrench as shown inFig. 201; to

close the wrench as shown in Fig. 1.

To hold the members parallel and permit longltudinal movement I providea sheet metal U-shaped casing 9 having sides 10 and Thiscasing receivesthe members 5 and 6 between its sides and its sides are rigidly securedto the member 6 by'rivets 12 and 13 and provides inclose the jaws 7 and8,'which are thus free to engage the article upon which the wrench is tobe used. I close the rear end of the casing by a filler end block 14,which is of providea pivotally mounted block 16 which is mounted at itsrear end on the rivet 13 so thatit can swing from and toward themember5. Y c

For the purpose oflocking the member5 with its jaw '7'relativelyfitothemember 6 and its jaw 8 so that the'jaws cannot separate, in use, Iprovide aworm screw 18 rotatably carried by the block 16 and adapted tothe housing in which the member 5 is longitudinally movable. This casingdoes not tween its rear end and the filler block 14 I be swung with theblock into and out of.

mesh with a screw rack 19 which I form on mounted in the member 16 atthe forward end of thenotch 20 and its rear end passes -through a'hole22 which I provide in the filler block 14. The rear end-of the'shaft 21projects beyond the block 14 and I se-.

cure a knurled head or button 23 on the outer end of the shaft and bywhich the worm screw 18 can be rotated to adjust the jaws "from andtoward each other when the screw is in mesh with the rack. W v

I pivotally mount the block 16 as described so that I can release therack from the screw, as shown in Fig. 2 to permit the.

quick and free relative movement of the outer 'aw 7 to open the wrenchand its free inwar movement to close the wrench.

' For swinging the block. 16 on its pivot and the screw into and out ofmesh with the rack, I provide a trigger lever 24 pivotally mountedbetween its ends to the sides of the casing on the pivot 25 and havingone. end 26 arranged to engage in a notch 27 in the forward end .ofthe'block 16 and 1 so arranged that, when-the triggeris swung Tao in onits pivot.

on its'pivot the block will be swung out or To lock the screw in therack I provide an inwardl'y'extending abutment 28 on the trigger and acooperating outwardly extending projection 29 onathe free end of theblock 16. The abutment 28 is in the path of the projection 29 asthemember 16 swings out and prevents the swingingof the member 16 untilthetrigger has been swung on 1 its pivot sufiicient "to permitv theprojection 29 to :pass the abutment 28 as shown in Fig. 2. Y

It is to be noted that theline of pressure of the contact ofthe'projection 29 against the abu-tment'28 passes substantially throughthe pivot 25 of the trigger 24 and that consequently the'lockin'gpressure doesnot tend to rotate the trigger and release the, worm.

There is sufficient clearance between the end .26 of the trigger. 24and'the walls of the .notch to permit the trigger to swing the abutment28 out of the path of the projec tion 29 before the same contacts withthe outerend thereof. The trigger 24 is nor- 'mally held in a lockingposition by a flat spring 30 mounted. in anopening 21 provided inthe'rear end of the member 6 and having'its free end clampe'd'ina slot32 provided in the member 6. T he spring 30 bears at -its'free'e'nd uponthe finger :end 33 of the trigger 24 and tendsito hold said endoutwardly, as shown in Fig. 1, where it can be conveniently pressed bythe finger of' th user to release the worm and .rack.

In order to cause the wvoifm' 18 to be moved inwardly in advanceof. theengagement of the abutment 28 and-projection 29, I provide a lightspring 30 substantially parallel withthe spring 30' and longenough sothat its fre'eend projects between the proj'ection 29 and abutment 28and formed to bear upon the-outer endof the projection 29 to yieldinglyhold the block 16 swung inwardly' as far "as the engagement of thetrigger therewith will permit. In consequence far enough of this theclearance between the end 26 of the trigger 24 and the walls of thenotch 27 ,the'block16, with the worm 20, is swung inwardly quick enoughso that the-projection 29 clears the abutment 28 as the trigger swingsback to locking position.

To cause themember 5 to be automatically retracted once it has beendrawn out, as shown'in Fig. 2, I provide a compression spring 34 mountedin an elongated notch 35 which I provide. in the backedge of the shank17 of the. member 5. The forward end 36 of the pring 34 abuts aprojection 37 secured to the-rear wall 11 of the casing 9 and the rearend 38*of the spring '34 abuts a projecting pa'rt 39 of the shank 1,7 ofthe member 5,'cons'equently when themember 5 is Withdrawnthe spring 'iscompressedand tends to push the member 5 back again.v

I make the spring 34 tapered as shownso that I canmake the notch 35correspondingly tapered in orderthatthe shank 17 at the forward end ofthe notch 35 will be as strong as possible. .I- guide this spring upon arod 40 which is somounted at its forward end in the projection-37 thatits rear end is threaded'through a ho1e'41 in the projection 39.' Imakethe forward .end 'of the rod smallerthanthe rear end to accommodatethe smaller diameter'of the spring at this end and 'I providea shoulder'42 on the rod against which the-projection 39 contacts to limit theoutward movement of the jaw 7.

I Once the 'jaw -7 has been drawn out the spring34 will retract itunlessthe member is held either by being placed upon the article, as anut upon which it is to be used or is held in some other way. The meanswhich I provide to control the retraction of the jaw 7 consists of a pin43 freely'movable in an opening 44 in the member6 and pro 'vided withahead 45 at its inner end adapted to frictionally engage the adjacentedge :x

. of the shank 17. of. the member- 5. This fi'ic-.

tional engagement is caused the further inward movement. of 'the freeend of the spr ng 30 after the trigger has been swung spring 34toretract the member 5 until the "j aws substantially fit the articleengaged.

It isobvious that if, he relieves the pini 43 of all pressure themember5' will be into release the worm. from the stantaneously retractedwith the whole force of the spring 34, it is also obvious that bymaintaining some frictional" engagement between the pin 43 and themember 5 the retraction of the member 5 can be controlled as desired. Ifa highly finished article is to be engaged, 1t might mar it to have themember 5 retracted with a hammer-like blow. Having allowed the member 5to be withdrawn so that the aws are in position to engage the article,the trigger is entirely relieved and the worm is forced back intocontact the rack by the spring 30 and the cooperating projections 28 and29 lock the worm in mesh. It is obvious, if at this time the worm shouldnot enter freely into the rack, that a slight rotation of the worm bymeans of the knurled head or button 23 will cause the thread of the wormto mesh with the teeth of the rack and the worm would then be forcedinto mesh by the spring 30. If the wrench does not now fit the nut orbolt head closely enough the jaws can readily be adjusted by rotatingthe worm 18 by means of the knurled head or button 23*to cause thedesired engagement of the jaws upon the article being manipulated Asmany modifications of my invention will readily suggest themselves toone skilled in the art I do not limit or confine my in vention to thespecific sctructures herein shown and described;

I claim:

1. In a wrench of the kind described, two relatively movable members, ascrew and rack connection for relatively moving members and for holdingthem in relatively adjusted positions, trigger means for locking thescrew in the rack and for swinging the screw out of the rack, a springresisting Separation of the jaws of the wrench, and a friction membermovable by; said trigger for controlling the closing action of saidspring.

2. In a wrench of the kind described, a

, screw and rack for relatively moving the I two aw members to ad ustthe aws, means for releasing the screw and rack, means normally lockingthe screw and rack in engaging relation, a spring for yieldinglyresisting the separation of the jaws, and

means for applying friction between the two lever engaging in a. slot inthe free end of said block for releasing the screw from the rack, andcooperating parts on the block and lever alined with the ivot of saidlever for locking the screw in t e rack.

4;. A wrench comprising two, relatively movable members, each carrying ajaw, a

rack on one member and a cooperating screw carried by the other memberfor relatively moving said members, a spring yieldingly holding the jawsagainst separation, a pivoted block in which the screw is rotaotablymounted, means for locking the block with thescrew and rack in mesh,means for unlocking and swinging said block on its pivot to release thescrew from the rack, and means for frictionally engaging the two membersto control the action of the spring in closing the jaws.

5. In a wrench of the kind described, two relatively movable memberseach having a jaw, a rack on one member and a cooperate ing rotatablescrew carried by the other member for relatively moving said members andfor holding them against relative movement, a spring tending to closesaid j aws together, a pivoted'block in which the screw is mounted, apivoted trigger for releasing the screw from the rack, the triggerhaving three operating positions, and adapted in one position to lockthe screw in the rack, in an intermediate position to lift the screw outof the rack, and means .en-

gageable by the trigger in its third posi tion for trictionally engagingthe rack member to prevent the retraction of the rack member by said sring.

In witness whereof I hereunto subscribe my name this 17th day of May,1919.

RUDOLPH LEHNHOFF.

